The LCD devices are most typical among flat-panel display (FPD) devices and are widely used as display devices for PCs and TV sets, for computer terminals, for vehicle-mounted display devices such as car navigators, and for mobile devices such as smart phones and other mobile phones as well as information terminals or digital assists. A display panel of the LCD device comprises an array substrate and a counter substrate, which are adhered to each other through a sealing material, as well as a liquid crystal layer interposed between these substrates.
The array substrate comprises in general, on its view area or pixel-array area, an array of scanning lines and an array of signal lines that intersect the scanning lines as well as a switching element and a pixel electrode at around each intersection of the signal and scanning lines. Mostly, the array and/or counter substrate have, on their outermost layers contacting the liquid-crystal layer, alignment layers that are typically formed of polyimide resin. The alignment layers are obtainable by forming a resin layer and a subsequent alignment treatment. By the alignment layers, liquid-crystal molecules contacting the alignment layers are aligned in a pre-set direction, at an initial state of no voltage application, and have a pre-tilt angle to a plane of the substrate in such initial state if and as required. The alignment treatment is typically made by rubbing the resin layer with a fabric that is called as a buff and wound around a roller. The alignment treatment may also be made by irradiating the resin layer, typically with UV lights.
When a patterned face of the array substrate or the counter substrate has a relief structure or microscopic slopes, liquid-crystal molecular orientation would be disturbed, and thus, image-displaying would be adversely affected.